Field of the Invention
The invention generally relates to a wireless communication technology, and more particularly, to a wireless communication method for activating a power-saving mechanism to stop monitoring a Physical Downlink Control Channel (PDCCH) when a Discontinuous Reception (DRX) mechanism is not configured or enabled by the network.
Description of the Related Art
Wireless communication systems have been used widely to provide various telecommunication services such as telephony, video, data, messaging, and broadcast services. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency divisional multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of an emerging telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrums, and integrating better with other open standards using OFDMA on downlinks (DL), and SC-FDMA on uplinks (UL) and multiple-input multiple-output (MIMO) antenna technology.
In an LTE system, user equipment (UE) needs to monitor a physical downlink control channel (PDCCH) to determine whether there is DL data transmitted form the network. However, the UE's monitoring of the PDCCH will consume battery power, and this power is wasted when the time slots have no control signaling for the UE. In LTE technology, a Discontinuous Reception (DRX) mechanism is defined to reduce monitoring power. FIG. 1 is a schematic diagram illustrating a conventional DRX cycle. As shown in FIG. 1 the DRX cycle comprises two parts: “On duration” and “DRX opportunity”. In On duration, the UE may still monitor the PDCCH. In the DRX opportunity, the UE will stop monitoring the PDCCH to save power.
However, in some networks, these networks may not configure DRX for UE. Therefore, the UE may still monitor the PDCCH when no data has been transmitted from the network for a long time, and as a result, the power of the UE will be wasted.